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Asteroid Close Approaches: Analysis and Potential Impact Detection
Andrea Milani (Univ. Pisa), Steven R. Chesley (JPL), Paul W. Chodas
(JPL) and Giovanni B. Valsecchi (IASF-CNR)
Chapter in Asteroids III (Eds. W. Bottke, A. Cellino, P. Paolicchi,
and R.P. Binzel) 2002.
ABSTRACT
Recently, several new tools and techniques have been developed
which allow for robust detection and prediction of future planetary
encounters and potential impacts by Near-Earth Asteroids (NEAs). We
review the recent history of impact prediction theory, and cover the
classical linear techniques for analyzing encounters, consisting of
precise orbit determination and propagation followed by target plane
analysis. When the linear approximation is unreliable there are
various suitable approaches for detecting and analyzing very low
probability encounters dominated by strongly nonlinear dynamics. We
also describe an analytic approach that can provide valuable insight
into the mechanisms responsible for most encounters. This theory is
the foundation of the impact monitoring systems, the ones currently
operational and the ones being developed.
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